A survey on labeling graphs with a condition at distance two
نویسنده
چکیده
An L(2, 1)-labeling of a graph G = (V,E) is a function f : V → {0, 1, 2, . . .} such that |f(x)− f(y)| ≤ 2 if d(x, y) = 2 and |f(x)− f(y)| ≤ 1 if d(x, y) = 2. The span of an L(2, 1)-labeling is the maximum value f(x) among all vertices x in V . The L(2, 1)labeling number of G, denoted by λ(G) is the minimum span of an L(2, 1)-labeling. A more general setting is as follows. For positive integers j1 ≥ j2 ≥ . . . ≥ jr, an L(j1, j2, . . . , jr)-labeling of a graph G = (V,E) is a function f : V → {0, 1, 2, . . .} such that |f(x) − f(y)| ≤ ji if d(x, y) = i for 1 ≤ i ≤ r. The span of an L(j1, j2, . . . , jr)labeling is the maximum value f(x) among all vertices x in V . The L(j1, j2, . . . , jr)labeling number ofG, denoted by λj1,j2,...,jr(G) is the minimum span of an L(j1, j2, . . . , jr)labeling. Notice that λ(G) = λ2,1(G). Most frequently studied case is when r = 2.
منابع مشابه
Product version of reciprocal degree distance of composite graphs
A {it topological index} of a graph is a real number related to the graph; it does not depend on labeling or pictorial representation of a graph. In this paper, we present the upper bounds for the product version of reciprocal degree distance of the tensor product, join and strong product of two graphs in terms of other graph invariants including the Harary index and Zagreb indices.
متن کاملTotally magic cordial labeling of some graphs
A graph G is said to have a totally magic cordial labeling with constant C if there exists a mapping f : V (G) ∪ E(G) → {0, 1} such that f(a) + f(b) + f(ab) ≡ C (mod 2) for all ab ∈ E(G) and |nf (0) − nf (1)| ≤ 1, where nf (i) (i = 0, 1) is the sum of the number of vertices and edges with label i. In this paper, we give a necessary condition for an odd graph to be not totally magic cordial and ...
متن کاملOn Total Edge Irregularity Strength of Staircase Graphs and Related Graphs
Let G=(V(G),E(G)) be a connected simple undirected graph with non empty vertex set V(G) and edge set E(G). For a positive integer k, by an edge irregular total k-labeling we mean a function f : V(G)UE(G) --> {1,2,...,k} such that for each two edges ab and cd, it follows that f(a)+f(ab)+f(b) is different from f(c)+f(cd)+f(d), i.e. every two edges have distinct weights. The minimum k for which G ...
متن کاملOn (Semi-) Edge-primality of Graphs
Let $G= (V,E)$ be a $(p,q)$-graph. A bijection $f: Eto{1,2,3,ldots,q }$ is called an edge-prime labeling if for each edge $uv$ in $E$, we have $GCD(f^+(u),f^+(v))=1$ where $f^+(u) = sum_{uwin E} f(uw)$. Moreover, a bijection $f: Eto{1,2,3,ldots,q }$ is called a semi-edge-prime labeling if for each edge $uv$ in $E$, we have $GCD(f^+(u),f^+(v))=1$ or $f^+(u)=f^+(v)$. A graph that admits an ...
متن کاملCOSPECTRALITY MEASURES OF GRAPHS WITH AT MOST SIX VERTICES
Cospectrality of two graphs measures the differences between the ordered spectrum of these graphs in various ways. Actually, the origin of this concept came back to Richard Brualdi's problems that are proposed in cite{braldi}: Let $G_n$ and $G'_n$ be two nonisomorphic simple graphs on $n$ vertices with spectra$$lambda_1 geq lambda_2 geq cdots geq lambda_n ;;;text{and};;; lambda'_1 geq lambda'_2...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Discrete Mathematics
دوره 306 شماره
صفحات -
تاریخ انتشار 2006